After upgrading to v2.8 today, any .less files that have @import statements in them are broken. I have found someone else having the same issue, on this stack overflow topic: http://stackoverflow.com/questions/17703093/web-essentials-v2-8-less-import-error/17735609#17735609
I am not receiving any error messages, just a blank preview window, along with blank .css and .min.css files, so my styling is now broken.
Do you have any ideas what is going on?
Thank you.

Unfortunately, I'm having the same issues. In 2012 it appears that the relative path bug has not been fixed, although I can use the @import as far back as one folder (../file.less) I believe. My project structure requires 3 levels up. I tried in 2012.2 and 2012.3.
Using the preview for 2013, no @import works. This is such a great addition to Visual Studio, it's such a shame that one single item keeps bogging me down.

When I write:
@import "/normalize/normalize.less";
#normalize.all("Arial", "Arial");
The css is compiled but #normalize is "undeclared.
Changing to:
@import "normalize/normalize.less";
#normalize is declared but the css doesn't compile.

After I upgraded to 2012.3 update (I think it's related), my LESS intellisense and syntax highlighting stopped working. web essentials apparently still work, as I can still see CSS preview (correctly syntax highlighted), LESS compiles and I can change options.
I just upgraded to 2.8 hoping this has been resolved, but I can see the same effect. No LESS highlighting nor intellisense.

Visual Studio 2012 Update 2
Web Essentials 2.7
Hello,
Every time when I try to change or create any .less file, I got this message in css preview:
/*
Compile Error.
See error list for details
*/
And when I open Error List, I can see this:
LESS:
This thing same everytime, no description at all. It doesn't depend from code, even this code generate error:
body {
}
What shell I do?